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Electric birefringence in the isotropic melt of a comb-like polyacrylate with mesogenic cyanobiphenyl side groups has been studied. A fraction with the degree of polymerization 200, which forms a smectic mesophase, has been considered. The change in the character of the temperature dependence of the Kerr constant has been revealed in the isotropic phase above the smectic–isotropic phase transition temperature. This effect is explained by the change in the character of short-range order in the isotropic–isotropic phase transition. 相似文献
95.
An Efficient Enantioselective Synthesis of Natural Gingerols,the Active Principles of Ginger 下载免费PDF全文
A. Ramesh Reddy Sachin B. Wadavrao J. S. Yadav A. Venkat Narsaiah 《Helvetica chimica acta》2015,98(7):1009-1017
A straightforward synthesis of (S)‐gingerols 1 – 3 has been described. The requisite stereogenic center in the target molecules was introduced by Sharpless asymmetric dihydroxylation using a chiral complex, AD‐mix β. This route is simple and efficient to prepare the products in very good yields. 相似文献
96.
Satska Yu. A. Komarova N. P. Gavrilenko K. S. Manoylenko O. V. Chernenko Zh. V. Kiskin M. A. Kolotilov S. V. Eremenko I. L. Novotortsev V. M. 《Theoretical and Experimental Chemistry》2015,51(1):45-53
Theoretical and Experimental Chemistry - It was shown that porous coordination polymers (PCPs) of 3d metals containing chiral centers in fragments of deprotonated (S)-lactic and (R)-aspartic acid... 相似文献
97.
98.
Synthesis of 2‐Unsubstituted 1,3‐Selenazoles by Cyclization of Selenoformamide with α‐Bromocarbonyl Compounds 下载免费PDF全文
Harald Below Wolf‐Diethard Pfeiffer Karlheinz Geisler Ashot S. Saghyan Christine Fischer Peter Langer 《Journal of heterocyclic chemistry》2015,52(2):592-596
2‐Unsubstituted 1,3‐selenazoles were prepared by cyclization of selenoformamide with α‐bromoacetophenones. Parent 1,3‐selenazole was prepared by cyclization of selenoformamide with α‐bromoacetaldehyde. 相似文献
99.
S. K. Amini 《Journal of Structural Chemistry》2015,56(7):1334-1341
The unassigned configurations of a toxic metabolite to mammals extracted from Neosartorya fischeri (fischerin) in C19, C20, C21, and C22 are assigned as R, R, R, and S, respectively. In this assignment, the extensive ab initio calculations followed by chemical shift computations are performed. Computed chemical shifts are correlated to experimental ones in order to find the correct configuration shown here. 相似文献
100.
M. Köse G. Ceyhan S. A. Güngör S. Purtaş V. McKee 《Journal of Structural Chemistry》2015,56(7):1353-1359
A pyridine–diimine compound N,N′-[pyridine-2,6-diyldi(E)methylylidene]bis(4-chloroaniline) is synthesised by a Schiff base condensation of 2,6-diformylpyridine with 4-chloroaniline in methanol and characterised by spectroscopic and analytical techniques. The molecular structure of the compound is determined by the single crystal X-ray diffraction study. The compound crystallizes in the monoclinic crystal system, I2/c space group with unit cell parameters a = 7.0843(12) Å, b = 6.1909(11) Å, c = 36.262(6) Å, β = 91.576(3)°, V = 1589.8(5) Å3 and Z = 4. There is an intermolecular hydrogen bonding in the molecule resulting in a 1D hydrogen bonding chain and these hydrogen bonding chains are linked by Cl…HC(aromatic) interactions forming a 2D network. Crystal packing of the compound is determined by Cl…HC and π–π interactions. In the fluorescence emission spectra in CH3CN, DMF, DMSO and EtOH, the compound shows only one emission maximum. 相似文献